Answer:
Distance will be 49.34 m
Explanation:
We have given wavelength 
Diameter of the antenna d = 2.7 m
Range L = 7.8 km = 7800 m
We have to find the smallest distance hat two speedboats can be from each other and still be resolved as two separate objects D
We know that distance is given by 
So distance D will be 49.34 m
Because there is no wind, rain, snow, sleet, or people to wear them down,
and no rivers, streams, or floods to cover them over.
The coefficient of friction is 0.5.
<h3>What is Coefficient of friction?</h3>
The ratio of friction force to normal force is known as the coefficient of friction (COF), which has no dimensions. Those materials are said to as lubricous if their COF is less than 0.1. Surface roughness and COF are dependent on the composition of the materials.
Initial velocity, u=30m/s
time taken = 6s
Final velocity, v=0
Acceleration of friction, a=μg=10μms⁻²
Apply first kinematic equation of motion,
v - u = at
0 - 30 = (-10μms⁻²) × 6
-30 = -60μ
μ = 1/2
μ = 0..5
Hence, coefficient of friction is 0.5
to learn more about Coefficient of friction go to - brainly.com/question/14121363
#SPJ4
Answer:
The angle will be 0 . The angle between the incident ray and the mirror is called angle of incidence while the angle between reflected ray and the normal is called angle of reflection. Here, the a ray of light is incident normally on a plane mirror.
Explanation:
The electric field 4cm from the wire is

Given:
charge is distributed uniformly along a long straight wire.
electric field 2cm from the wire is 20n/c
To find:
electric field 4cm from the wire
what is electric field?
Electric field is the region around charge particle or charged body in which if another charge is placed it experiences electrostatic force.An electric field is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them.





thus the electric field 4cm from the wire is

learn more about electrostatic force from here: brainly.com/question/28166144
#SPJ4